How to do MailChimp MERGE field with ADDRESS type

pmpro-mailchimp-merge-with-address-field.php

<?php
//Address merge types must be handled in a very specific format
function my_pmpro_mailchimp_listsubscribe_fields($fields, $user)
{
	$user_info = get_userdata($user->ID);
	
	$new_fields =  array(
	"FNAME" => $user->first_name, 
	"EMAIL" => $user->email, 
	"LNAME" => $user->last_name,
	"ADDRESS" => array( 'addr1' => $user_info->pmpro_baddress1,
                            'addr2' => $user_info->pmpro_baddress2,
                            'city' => $user_info->pmpro_bcity,
                            'state' => $user_info->pmpro_bstate,
                            'zip' => $user_info->pmpro_bzipcode,
                            'country' => $user_info->pmpro_bcountry)
      );

    $fields = array_merge($fields, $new_fields);
      
    return $fields;
}
add_action('pmpro_mailchimp_listsubscribe_fields', 'my_pmpro_mailchimp_listsubscribe_fields', 10, 2);

Please also note that if the fields you are sending are new merge fields, they must first be created in Mailchimp.

You can do this manually through the Mailchimp dashboard or use the pmpro_mailchimp_merge_fields filter to create them through the API like the example recipe here: https://gist.github.com/dparker1005/13ab3295d92818b3e46c53b0ca0268ba

This recipe is included in the blog post on "Send a Member’s Address Fields to Mailchimp" at Paid Memberships Pro here: https://www.paidmembershipspro.com/send-members-address-fields-mailchimp/